Bucken for turbines



I8 0 3 mu H. HOLZWARTH BUCKET FOR TURBINES Filed Aug. 25, 1921 81 L, w we M. m H, WW m IL 7 I 0 w, g y g W N v w 4 w/ ///////J// A -w;

July 14, I925.

1'. mm 1W0. ssssss.

s25 'wimn ii; may

mus mmmsr wishoufl; intsrmpfion Mai the Es it gerlsmtsd pressure upon the; indivichml or blades 15 gsnssslly mlmawsly gas @1 explosion tmbmes, an the 5 contrary the energy which is lihemmd by szs'plosian is sflsctxvs as a, jet of gas, spam 1th bucizs 01* Made 5011- only a. wry short 1;: be izm'l s53 time Altog'suihsxg-enly about was U '3" Cm'ifll sscnn. is available 01 such ones- 10 ms :iar Us shim i10- novel and I Knussdistsly thereafter zihs driving waved msans sf'con'sxs u um buckets ii at a, given sxpiosisn chmmbew wish ii-11s tmhim Whesl m: r. smsss as she latter must be cooked with air (f he): more snesisc objss'as of [ha and hE-hen' Msdsd with a frssh @hsrgs sf ex:-

Fmm the desm-lptisn hsmim plssivs mixture. Tbs buckets elibisdss f ad? novslty wilii bs saplosion turbines am therefore subjecfissd tea? mi; in Lbs sppsnsd 11s rsisiivsly sharia but powsrful News as tbs sscaxnpsny. dmwing, W1 hi1 the sssuii; of successive sxp losionsv Thesv lustrstssj slmm 185 sf my invsntim sampsnying high tempsmtures (400 to 450 fining its iiinits, iiigms 1 is GI} rsstlg ici fijileconssr ucimfis chsice to only 512:, sesf mnsl View shawin gg the m 1 01 s baited number of diifiersnt materials far shs'mtos'md a bucks 01: blade; connsstsd pasts of the turbine. Becsuss 01% this,

thsrswiti; in my 21s a and m n-med manthe cmishruciion 0f the stem @1' 150015 015' ike new; is s sizmhu ViEW was 21* bucim'i; or blsds, Whmh must be of grsslb farm 0 my isvsntion 0n tl'zs 2m 3? -2 0f strength 1s of sspscml c0nssqusncsv 2L Fig. tbs Emits! bein a .ssction on tbs line With steam turbines 0%? existing constmw 0f a parties of 1 eniz'u'geii scale, with parts broken sway,

tum, 5 Lpmssnss the fir-s6; series are seamed, by means at $11611 stems 01' feet, sgamst the generated, centrifugal. forcs. It Wags/hers mp/e and {5 tbs 120%, possible, for these rsssens, ts con 10 1s formed stx'uct ths blades 01' such siaeam turbmes re s I si oppcsits, 5mm dawn bars and to mserb them mm 1m; pmvided with s Tbs bucket 01? Made suitsbie and WM 11 csntinm miss sides or s'th i1 profiled recesses, with syncing members inserted. between sash two buck ts 0!; blades and to fasten the Whole in plscs Wish light hammer blows, 01' the spacing members and basins-ts wuld bs taken :bogshsr, the busksi;

t and its stem 01 just being forged 01' other.-

. 1 acted as fit Wise (:(mstructed i1: mm piece, and, 1311s bucksfi 1 wi. up 11mm i'u iiy ss'zsm or .Eoot again plscsd' in rscsssss 0f the .ilersim 'ii'm s r {00%; 1O farmed turbine whesl or inter and fixsd in. piacs. with slit vanish csm srgss 1n the case of steam turbines, arrangsmsms and of said 00 2", Hu 2 ts we; pointed are also known in which the bucket stsm is toward ill E7 on siitted from below mi d aha bucket is pressed Ths arm incluc'lss a from uboveia spread apart the I'JWO sides wedge .13 sciupzmj. ts slit and m: flanks of we buckst stem. and; thus pm rest Witl'l ii-s bass up a rscess *4; both. she; slit i2; csntmiugai im'cc. vIn sddmon with swam addition to squaring iQGWE 'ZTi mrbmsg arrangements axis; 111 whenv a 09 end of 31,

simpsd in. s 5 01', more rsqsss Y 1' Wsdgs or the like is driven in press the of the) bushes (22." T3005; sidswsys 5%; wins 1 m whssL vids constant safety against. tbs .zgensrstsd eration of gas turbines. These existin constructions of the bucket stems, as state take into consideration only the centrifugal force which is generated; under the effect of generated blows and high bucket pressures they give and yield. In such case, the buckets, as the blows are delivered, pound with the flanks of the stems or feet against one'another and against the rotor and thereby become loose. These slight vibrations against each other and against the rotor become constantly greater and finally result in breakage of the buckets or blades. In all existing constructions of the bucket stems the permanent tension against the periphery or rim of the rotor and against adjoining buckets orblades is missing. Without this permanent tension the buckets or blades, whensubjected to short blows, as in the operation of internal combustion turbines, must become loosened.

According to the present invention the fastening of the buckets or blades is accomplished in such a manner that the stem or foot of the bucket or blade slitted and provided with profiled sides or flanks, is secured through the medium of a wedge which sets upon the bottom of a circumferential recess of the rotor and is driven into place in the direction of said recess; that is to say,

the wedge 13, with its base resting upon' the bottom of the recess 7 in the rotor rim 6 is driven into the slit 12 in a direction tanential to the rotor and thus presses the dunks of the stem 10 sideways. In this manner large, transverse pressures and also large, radial pressures are exerted against the bucket stem or foot. "By means of the transverse pressures the teeth 11 are firmly pressed into the grooves 8 while through the medium of the radial pressures the bucket is pressed outwardly in the direction of the centrifugal force which is subsequently generated, to pressthe flanks or sldes of the teeth 11 against the contiguous surfaces of the grooves 8. In this way the entire bucket or blade is placed under ten- .sion relatively to the rim of the rotor and,

through the described arrangement, is maintained under tension, during the operation of the turbine, a 'ainst anybucket pressures, bucket pushing, bucket blows or centrifugal efi'ects upon said buckets which may be generated. Instead of an individual wedge for each bucket, a wedge common to aplurality of buckets may be used.

It will be noted that the two surfaces or flanks of each of the teeth 11 are inclined in opposite directions, that is, the flank 11 nearer the center or axle of the rotor is inclined inwardly from the tip of the tooth toward the wedge, while the outer flank 11", of the tooth is inclined outwardly. The corresponding walls 8, 8", of the grooves 8 are also inclined in opposite directions from r the tip of the tooth toward the wedge. Furthermore', it will be noted that the outer flanks ll" of the teeth 11 (and the corresponding outer surfaces 8" of the grooves 8) are inclined outwardly at a smaller angle than the sides of the wedge 13, so that the said outer flanks and the adjacent side surfaces 13' of the wedge 13 converge outwardly, that is to say, away from the axis of the turbine. Both of these features contribute to hold the bucket stem 10 firmly within the recess of the rotor rim 6.

The wedge is constructed of material which is relatively harder than the bucket stem and drives the toothed flanks thereof into the grooves of therotor rim and war rants a minimum of strains upon the flanks of the teeth from outside forces. To maintain this advantage in the case of high driving temperatures, the wedge miist be protected against the direct influence of temperature; that is, must be relatively high and the wedge must be located in its lower; protected portion. Accordingly, the advance or taper of the wedgeis so arranged that the pressure exerted upon the bucket by the jet forces said bucket upon the-,wedge.

In some instances, additional security may be obtained by utilizing the arrange ment shown in Figs. 2 and 3. In this case, locking buckets or blades 9 are located at intervals and are provided with extensions 14 which project through the recess 7 and into pockets 15 extending radially inward therefrom at the proper points. The extensions 14 are to register with slots 17 in the rim 6, through which wedges 18 are forced so as to extend transversely to the recess 7, as shown in Fig. 2; the opposite sides of the extensions 14 diverge outwardly in engagement with correspondingly formed surfaces of adjacent buckets or blades 9, as shown at 20 in Fig. 3. lVith this arrangement the wedges, by bearing against the walls of the slots 16 and 17, draw the bucket 9 inwardly toward the centre of the rotor 5 and clamp it in place and at the same time cause the surfaces 20 to exert a clamping action upon the adjacent buckets or blades 9, whereby the rigidity of the connection between the latter and the rotor is still further increased.

In this way the blade or bucket ring or series is interrupted less often than has, up to the present time, been the case, and a greater number of blades or buckets may be included in a ring which, particularly in large gas turbines, is of special advantage.

arious changes in the specific forms shown and described may be made within the scope the jet of the claims without departing from the the bucket stem or foot provided with slots 16 adapted .i aaa aoo eomtioatioo of a "-l'wwiif a circumferb We a n ul bucket having a 5 o oviclecl with teeth aroor' os' and a Wedge bottom of oiElCl. 011- eoiol wedge being tapered .l ros anti in a direction tan- I rotor whereby said teeth are trarmvcrsely into eaicl grooves and outer 5. its oi said teeth are radially .a t the walls of said grooves in l e siirection of the contriiugai w cl when the turbine in op a {for generate eratloo 2 In. an, l1?"".'fi:li combustion turbine, the combination of a rotor ha ing circumferential provided with plurality oi grooves in o posito walls, a bucket said bucket having a tapering provided with teeth arraj ed to lit sari-cl groovee and means. within said recess whereby said teetlr are oresseti transversely into eaicl grooves the outer "limits the teeth are r 1 Presser the oooose i of said. grooves in A eot fag'al iforoe gerodo the tur'hi in operation. an ii'zterilal cc 3 stion turbine the olf a to having a oircunr V with a plurality oeito Walia said rotor trarrsverse slots comi c TS, piuraiity of brackets provided with lit grooves, means are transversely \G'VES, rookie buckets located at in registry with svw'sc extending ts ted co-ooeratmg surfaces 8 buckets and contiguous the are oiampet i said trair'w combustion turbine, a

(1)81 Limo;

having ooclcct having a stem having of the Wedgc both away from the center of the rotor anl against the side walls of said receas.

6. The combination of a rotor having a circumferentiai recess, a bucket having a stem. fitted into saicl recess, said. stem having a slit extending-circumfcrentially of the rotor, and. a wedge fitted into said-slit and. tapered both oircumierentially of the rotor and outwarcliy, to expand the slit stem against the side Walls of said recess and also away from the center of the rotor,

7. The combination of a rotor having a circumferential recess, a bucket having a atom fittea into saici recess, said stem having a slit extendling ciroom'ferentially of the rotor, and a Wedge fitted into saicl slit and tapered circmnierentially of the rotor to expand the slit stem against the side Walls. of said recess.

8. The combination of a rotor having a circumferential recess having in its side a circumferential Wedge-shaped groove, the surfaces of which izociiuecl inwardly and outwardly respectively, a bucket having a stem fitted. into said recess, and provide& or]: its side with a circumferential wetigew shaped tooth, the flaoka of "which are 11% clined ootwarolly and. inwaraiiy respectively to fit the surfaces of grooye, and mealie for forcing" stem against the Walls: oft said 'recess to dritc tho said tooth into said Wedge-groove.

S). The combination of. 'l'0iM3E"i'1WiDg a circumferential recees provided in its opposing eioloe "with circumferential ,Wefigo shaped grooves, each having one surt'ace m ciioedinwarclly and the other outwardly,

bucket having a oplit stem fitted into said recess, said stern hemg provnicd on eaoii or? Bit Nil

rue rte teeto into saw elxapeol grooves, each haviiw one surface in- P17 l choc i inwardly an l the other outwardly, a

lnioket having" a split stem fitted. into said recess said stem being pro'vidctl on each.-

o'lf its sides with circumferential wedgeol'wapotl LQQtllBELCil having one of its flanks inclined outwardly and the other inwardly to fit the respective surfaces of the correspomiiog groove, and. a wealge fittecl into Saki split 'oucket stem to force its tooth-into said wedge-grooves, the inclined outer surface of a groove and the adjoining, surface of said wedge converging outwardly.

11. The cdinbination fife; rotor having. a circumferfifitial recess and a transverse slot communicating with said recess, buckets provided with stems fitted into said recess, one of said buckets being a locking bucket having surfaces to force the adjacent buckets apart circuinferentially upon a radial movement of the locking. bucket, said locking bucket also having a slot to register with said slot of the rotor, and a transverse wedge adapted to be driven into said slots to force the locking bucket radially.

' 12. The combination of a rotor having a circumferential recess and a pocket communicating with said recess and extending therefrom toward the center of the rotor, buckets provided with stems fitted into said recess, one of said buckets being ailocking bucket, extending into said pocket, and

"'means for fastening said locking bucket.

In testimony whereof I have hereunto set my hand.

HANS HOLZWARTH. 

